Wiki info about Yak-9T

The Yak-9 was a Soviet single-engine fighter of the WWII era. It was the first combat aircraft designed by Alexander Yakovlev's construction bureau. The most mass-produced Soviet fighter of the war, it remained in production from October 1942 to December 1948, with a total of 16,769 built.
The Yak-9 was a further modification of the Yak-1 and Yak-7. In its core design, it was a redesign of the Yak-7. With few external differences, Yak-9 was at the same time much more advanced internally. This is not unexpected, as almost two years of design and combat experience of the Yak series went into the Yak-9. Also, at the time aluminium was in much greater supply than it had been two years previously at the start of the war. Amongst other things, the use of metal allowed the plane’s weight to be significantly reduced, meaning that more fuel could be stored and that the aircraft could be equipped with more powerful armament and more specialized equipment.
The Yak-9T variant, for instance, had an incredibly powerful 37mm NS-37 cannon firing through the propeller hub. Due to the length of the gun barrel, the pilot’s seat had to be moved 40 cm aft, and the airframe was strengthened. The variant carried 30 to 32 cannon shells, as well as 200-220 rounds for the synchronized UB machine gun. Salvo weight for the variant was a whopping 3.74 kg (8.24 lbs). The 37mm gun allowed for fire at increased ranges, up to 1,200 yards against bomber formations, and 500-600 yards against single non-maneuvering bombers. The Yak-9T was also successful against ground targets. Armor-piercing shells, fired from 500 yards at an angle of 45 degrees, could penetrate 30mm of armor. In late 1943, the Yak-9T was used in an anti-shipping role in the Black Sea. A total of 2,748 Yak-9s were built between March 1943 and June 1945.